Process of treating ores preparatory to smelting



- UNITED [sTATEs PATENT OFFl CE.

JULIUS HEGELER, OF DANVfizLE, ILLINOIS.

PROCESS OF TREATING ORES PREPARATORY '10 SMEIQTING,

No Drawing.

To all whom it concern:

Be it known that I, JULIUs W. Hneniinn, a citizen of the United States,and resldent of Danville, in the county of Vermilion'and- State ofIllinois, have invented a new and useful Improvement in Processes ofTreating Ores Preparatory to 'Smelting, of which the following is aspecification.

This invention relates to the art of zinc ore smelting and relatesparticularly to a preliminary treatment of the ore prepara-- ture intothe retorts of a smelting furnace,

said retorts being heated to such a temperature as may necessary toreduce the zinc to metallicform and to distil the same.

It is also recognized that for the efiicient and economic smelting ofthe charge, itis necessary that the ore and reducing agent shall becrushed or reduced to granular form of desired fineness and thoroughlymixed so that the ore and reducing agent shall be in intimate physicalassociation and contact'with each other, while at the same timeproviding sufficient porosity or openness in the mass to permit freeaccess of heated gases generated in the subsequent smelting'operation toall parts thereof andfree escape of the zinc fumes produced bydistillation of the metallic zinc liberated as a result of the reactionbetween the zinc ore and carbon contained in the charge.

In their very nature, these conditions are conflicting, as the finer theingredients are crushed the better as regards their intimate associatlonand contact, whereas-the coarser .the granulation, the better as regardsthe porosity or openness of the mass, and where the granular ingredientsare charged into the retorts in a loose mass the size of the particlesmust of necessity be a compromise etween these extreme conditions,thereby correspondingly impairing the most efficient operation of thefurnace. 'Another serious objection to charging the mixture into the.

Specification of iletters Patent. Application filed April 9, 1920..Serial No. 872,433, S

( Patented May retorts in the form of a loose mass is, the tendency ofthe ingredientsto segregate in transportation. and handling between themixer and the-retorts.

Extensive tests andexperiments have been made to meet the idealconditions of intimate association and requisite porosity by crushingthe ingredients to any desired degree of fineness and bri noting themixture by means of a suitable blnder.

because of complications which arise in its practice and also on accountof its excessive cost. The object of my invention. is to overcomethe objectionablefeatures inherent in the foregoing processes, and to this end,

it consists in mlxing properly prepared ore and coking coal or othercoking material 1n such proportions as may be desirable, both the oreand coal having been previously reduced to granular form of any degreeof fineness that will give the most desirable results, said mixturebeing made as homogeneous and uniform as possible. Said mixture is then'coked under conditions best suited to the particular character of thecoal- :or other coking material employed, whereby the volatile portionsof the coal will be driven off, either wholly or in such part asexperience shows will give the best results with diiferent ores andcoals or other coking materials in the subsequent smelting operation,the entirecharge coming from the oven in the form of coke in which theore is firmly embedded or cemented and throughout whichit is thoroughlyand uniformly disseminated, the ore particles being also impregnatedwith carbon. The coke is then crushed to any degree of fineness,

which-when charged into the retorts of the smeltlng furnace-will mosteffectively promote the accessibility and diffusion of heated gasesproduced b the smelting operation to all parts of the c arge, and theescape of metallic fumes and vapors therefrom. 7

As is generally well knownto persons familiar with the zinc smelting artas at present ractised, where the granular ore and car on necessary forreduction are charged into the retorts in the form of a loose,non-coherent mass, there is a tendency toward segregation in transportand handling from the time the material eaves the mixer until it ischarged into the retorts, and that, as segregation results, it'willdestroy in large measure, that intimate associa- This system j "18objectlonable from apractical standpoint tion and contact of the oreandcarbon necessary for the most effective reduction of the orecontained in the charge. By my improved process,'segregation of the orefrom the carbon is prevented and the intimate association and contact ofthe ore and carbon assured, due to the fact that'the ore and carbon maybe charged into the coking ovens directly from the mixer. When coking ofthe coal or other cokin material occurs, the desired intimateassoclation and contact of the particles of ore and carbon become fixedand will not be destroyed or inany way impaired or affected bysubsequent handling. v

I have found in practice that this intimate and fixed association andcontact of the particles of ore and carbon result both in a verymaterial acceleration of the subsequent reduction and distillation ofthe ore with a corresponding increase in the daily capacity and yield ofthe retorts, and also in the recovery of'an appreciably largerpercentage of the metal contained in the ore.

In the smelting of zinc ore, it is desirable to prevent the formationand segregation ofinolten slag, which not only tends to settle to thebottom of the retorts, corroding the same and materially reducing thelife thereof, but by adhering to the sides of the re torts, renders itdifficult to properly clean the same-that is to remove the residuetherefrom-and through improper cleaning reduces the capacity thereof,thus correspondingly reducing the size of the charge and the output ofthe furnace. By my im proved process, these objectionable features areeffectively overcome, as it is found that, as the smelting processprogresses, the nonfusible carbon particles in thecharge and the ashwill form 'a porous, spongy mass,

throughout which the fusible constituents lar form, my inventioncontemplates the addition to the mixture of other materials or reagentsdeslrable to be used in the final charge introduced into the furnace,thereby-insuring not only an intimate and fixed association and contactof the particles of ore and carbon, but a correspondingly intimateassociation and contact to the other materials or reagents contained inthe charge.

It is generally recognized that, in smelting zinc ore, the effectivereduction of the ore and distillation of the metallic zinc is promotedby the presence in the charge of a small percentage of volatilehydrocarbons and in accordance with my invention, the

presence of such hydrocarbons may be obtained by properly regulating thetemperature at which coking is efiected.

In addition to the foregoing advantages,

I have discovered that the coking of the coal or other cokingconstituents of the charge may be effected in ovens of the byproductscoking type and that the usual byproducts distilled in the cokingoperation will be unaffected by the presence of the zinc ore and will beequally available for all commercial and economic purposes as are theby-products distilled from coke or other fied, is added the value of theby-products' recovered, the economic results of my improved process verygreatly exceed those of any smelting process of which I have anyknowledge. I

For the reasons stated, my. invention contemplates the coking of thecoal orother coking constituents of the mixture in ovens of theby-products coking type.

The term coking coal as used herein is intended to include all coals ofthe bituminous .type which have a suflicient amount of the binding orresinic constituent to form a coherent mass upon the application of heatto the point of decomposition or in the ordinary process of destructivedistillation. In.

the intent and meaning of the term, all caking coals are considered tobe coking coals. In the same manner, the term other coking material asused herein is intended to include pitch residues from the distillationof tar, petroleum or asphaltic material which, upon the application ofthe usual processes of carbonization, will result in the formation of acoherent mass of coke.

To recapitulate, among the important advantages of my improved processof treating ore preparatoryto smelting as compared with any otherprocesses of smelting of which I have any knowledge, are the followingY 1. It increases the percentage of metal recovered in the smeltingoperatlon;

2. It accelerates the smelting operation, thereby correspondinglyincreasing the daily capacity of the furnace;

3. It materially reduces the quantity of carbonaceous material necessaryto reduce the ore; a

4. It prevents separation of slag with its attendant objectionableresults; and

correspondingly increasing the practical and commercial value of theprocess.

What I claim is 1. In the art of zinc-ore. smelting, a preliminarytreatment of the ore for the pur pose of producing a fixed mixture ofzinc ore and carbon, which consists in intimately associating andcommingling zinc ore and coking coal or other coking material, and inthen. subjecting said mixture to a coking process, substantially asdescribed. g

2. In the art of zinc ore smelting, a preliminary treatment of the orefor the purpose of producing a fixed mixture of zinc ore and carbon,which consists in. intimately associating and commingling zinc ore andcoln'ng 'coal or other coking material and in then subjecting saidmixture to a coking process under conditions which permit of therecovery of the by-product constituents of the coal, substantially asdescribed.

3. In the art of zinc ore smelting, a pre-' liminary treatmentof the orefor the purpose of producing a fixed mixture of zinc ore and carbon,which consists in substantially associatingand commingling zinc ore andcoking coal or other coking material in granular form, and in thensubjecting said 'mixture to a coking process, substantially asdescribed.

l. In theart of zinc ore smelting, a preliminary treatment of the orefor the purpose of producing a fixed mixture of zinc ore and carbon,which consists in intimately associating and commingling zinc ore andcoking coal or other coking niaterial, fixing said 'mixture bysubjecting it .to a coking process, and in then reducing the coked massto pieces ofdesired size for smelting, sub stantially as described.

5. In the art of zinc ore smelting, a preliminary treatment of the orefor the purpose of producing a fixed mixture of zinc ore and carbon,which consists in intimately associating and commingling zinc ore andcoking coal or other coking material in granular form, subjecting saidmixture to a coking process, and in then reducing the coked mass topieces of desired size for smelting, substantially as described.

6. In the art of zinc ore smelting, a preliminary treatment of the orefor the purpose. of producing a fixed mixture of zinc ore and carbon,which consists in intimately associating and commingling zinc ore andcoking coal or other coln'ng material, and in then subjecting saidmixture to a coking process under conditions which will efiectdistillation of a part only of the volatilehydrocarbons, substantiallyas described.

7 In the art of zinc ore smelting, a preliminary treatment of the orewhich consists in intimately associating and commingling zinc ore andcoking coal or other coking material, subjecting said mixture to acoking process, and granulating the coked mass to form pieces of desiredsize fordis-

